1. Field of the Invention
This invention relates to a pipetting apparatus for pipetting a liquid and a method of pipetting a liquid.
2. Description of the Prior Art
A pipetting apparatus for pipetting a liquid for pipetting a desired amount of the liquid and the corresponding method are known.
In the prior art pipetting apparatus and the method, at first, a desired amount of a liquid is sucked into a pipette through the nozzle thereof. Next, the pipette is moved to a position above a vessel or the like and discharges the liquid through the nozzle. During this operation, it is frequent that a dope of the liquid remains at the tip of the pipette. In the high accuracy pipetting operation, to take the drop of the liquid into the vessel, the tip is touched to an inner wall of the vessel such that the drop is coated on the inner surface, which is so called tip-touching operation. Further, the drop on the inner surface of the vessel is dropped with a centrifugal apparatus to move the drop toward the bottom of the vessel, which is so called spin-down operation.
The aim of the present invention is to provide a superior pipetting apparatus and a superior method of pipetting a liquid.
According to the present invention, a first aspect of the present invention provides a pipetting apparatus comprising: a pipette having a nozzle; pipette holding means for holding said pipette; a piston fluid-tightly sliding along an inner wall of said pipette; piston holding means for holding a portion of said piston; and instantaneous position changing means for changing a position of said piston with said piston holding means by a short distance with respect to said pipette holding means to jet a portion of a liquid in said pipette through said nozzle as a drop.
According to the present invention, a second aspect of the present invention provides a pipetting apparatus based on the first aspect, wherein said instantaneous position changing means comprises a motor, said pipetting apparatus further comprises moderately position changing means for moderately changing said position of said piston with said motor to suck and discharge a desired amount of said liquid, and said motor is commonly used between said instantaneous position charging means and said moderately position changing means.
According to the present invention, a third aspect of the present invention provides a pipetting apparatus based on the first aspect, wherein said instantaneous position changing means comprises a piezoelectric actuator.
According to the present invention, a fourth aspect of the present invention provides a pipetting apparatus based on the first aspect, further comprising an attachable nozzle cap being attachable to said pipette and having a nozzle-cap nozzle (through hole) for jetting said portion of said liquid through said nozzle and said nozzle-cap nozzle, a diameter of said nozzle-cap nozzle being smaller than that of said nozzle.
According to the present invention, a fifth aspect of the present invention provides a pipetting apparatus based on the first aspect, further comprises; detection means for detecting said portion of said liquid jetted from said pipette; and confirming means in response to said instantaneous position changing means and said detection means for confirming that said portion of said liquid is jetted and outputting a confirmed result.
According to the present invention, a sixth aspect of the present invention provides a method of pipetting a liquid with a pipette and a piston fluid-tightly sliding along an inner wall of said pipette comprising the steps of: (a) sucking said liquid with said piston; and (b) instantaneously changing a position of said piston with respect to said pipette by a short distance to jet a portion of a liquid in said pipette through said nozzle.
According to the present invention, a seventh aspect of the present invention provides a method based on the sixth aspect, wherein said step (b) is repeated to jet a desired total amount of said liquid.
According to the present invention, an eighth aspect of the present invention provides a method based on the sixth aspect further comprising the step of determining said short distance in accordance with a desired amount, wherein in step (b), said position of said piston is changed instantaneously by said short distance determined in accordance with said desired amount.
According to the present invention, a ninth aspect of the present invention provides a method based on the sixth aspect, between the steps of (a) and (b), further comprising the steps of attaching an attachable nozzle cap to said pipette at said nozzle, said attachable nozzle cap having a nozzle-cap nozzle (through hole) of which diameter is smaller than that of said nozzle; and changing said position of said piston to fill with said liquid in said attachable nozzle cap, wherein in said step (b), said portion of said liquid is jetted through said nozzle and said attachable nozzle cap.
According to the present invention, a tenth aspect of the present invention provides a method based on the sixth aspect, further comprising the steps of: detecting said portion of said liquid jetted from said pipette; and confirming that said portion of said liquid is jetted in response to said instantaneous position changing means and said detection means and outputting a confirmed result.
According to the present invention, an eleventh aspect of the present invention provides pipetting apparatus comprising: pipette holding means for holding a pipette having a nozzle and a piston fluid-tightly sliding along an inner wall of said pipette; piston holding means for holding a portion of said piston; and moving means for moving said piston toward said nozzle by a short distance with respect to said pipette holding means for a short time interval to jet a portion of a liquid in said pipette as a drop through said nozzle.
According to the present invention, a twelfth aspect of the present invention provides a pipetting apparatus based on the twelfth aspect, wherein an amount of said drop is determined in accordance with a size of said nozzle, said short distance and said short time interval.